Machine tool



Oct. 26, 1937. A. OBERHOFFKEN ET AL 2,096,754

MACHINE TOOL Filed Feb. 18, 1935 5 Sheets-Sheet l mNTOR$ lcg/e;c%'e Ober/m/f/(en or 7 0402)? 6. W 4 W 7%.W.

(HTTOQIEQ/S Oct. 26, 1937. A. OBERHOFFKEN ET AL 2,096,754

MACHINE TOOL Filed Feb. 1a, 1935 5 Sheets-Sheet 2 s n a 6 N w, a m w 0% .T mww 0 Z Z WW Mi *5 sheets-shet 3 Oct. 26, 1937. A. OBERHOFFKEN ET AL MACHINE TOOL Filed Fep. 18 1935 s W a n w w a9 a 2 x M o m N E M A 6 [W m M 5% w o/u T p 4 Mom W W M T 7J 0 5 d I x/ M a m a ME m EE "u U 9 Ev rm U HHIHHHH m 1U Oct. 26, 1937. A. OBERHOFFKEN ET AL MACHINE TOOL Filed Feb. 18, 1935 5 Sheets-Sheet s,

5 n JN Ma w a m mwwffl Vbw r N0 WJBW M Z @m/ m Patented Oc 26, 1937 UNITED STATES MACHINE TOOL Alexander Oberhofiken and Earl M. Bowen, Rockford, IlL, assignors to The Ingersoll Milling Machine Company, Rockford, Ill., a corporation of Illinois I Application February 18, 1935, Serial No. 6,980

2 Claims.

This invention relates to machine tools for performing various metal-removing processes such as drilling, milling, tapping, boring, reaming, etc. and has more particular reference to machine tools of the multiple spindle type for forming or machining a series of holes in a work piece.

In practice, it frequently happens that a number of holes spaced in apredetermined relation must be drilled or boredin a work piece and afterwards the same holes must be tapped or otherwise finished. Where production requirements permit, a substantial saving of capital investment in machinery may be efiected by performing several ofsuch operations in one machine tool.

The primary object of the present invention is to provide a novel tool head construction by which conversion of a machine tool or the performance of any one of several difierent material-removing processes may be facilitated.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- 1 Figure 1 is a perspective view of a machin tool .embodying the features of the present invention.

Fig. 2 is a perspective view of the power mechanism and the drive connections extending therefrom.

Fig. 3 is a fragmentary view of the tool unit and work fixture with certain of the parts broken away or shown in section.

Fig. 4 is a view similar to Fig. 3 with one set of tools removed from the tool head.

Fig. 5 is a sectional view through a spindle supporting one of the tapping tools. Y

Fig. 6 is a fragmentary sectional view of the coupling for connecting one of the tool spindles to its drive shaft. 7

Fig. 7 is a wiring diagram. Fig. 8 is a fragmentary sectional view of a portion of the cycle controlling mechanism.

Fig. 9 is a fragmentary sectional view showing describe in detail the preferred embodiment, but

it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and ,alternative constructions falling within the spirit invention is shown in the drawings as embodied in a horizontal one way machine tool of the multiple spindle type for drilling a plurality of holes I in a work piece 2 and tapping the same holes. While being operated upon, the work piece is suitably clamped in a fixture indicated in 'outline at 3 and mounted on a pedestal 4. In the exemplary machine shown, the tools, which may be drills 5 or taps 6, are rotatably supported-by a unitary head I which is arranged to slide bodily along parallel ways 8 on a machine bed 9. .The head herein shown comprises a self-contained power unit l0 and a separate demountable tool or spindle carrying unit H both mounted on a saddle or carriage l2 having surfaces complemental to and fitting slidably in guideways 8.

In the form shown, the power unit I0 is of the electric type and comprises generally a casing l3, a reversible electric motor l4 (Fig. 2) therein for imparting rapid traverse motions to the tool head and a reverslble'electric motor I! for imparting positive feed motions in opposite directions to the head and also for rotatingthe tools in synchronism with the feed motions;

The rotary motion produced by operation of the motors l4 and I5 either simultaneously or independently is combined by a differential gearing l6 and converted into bodily rectilinear motion of the saddle l2 by two relatively rotatable feed elements which preferably comprise a screw l1 stationarily anchored to a plate l8 (Fig. 1) on the machine bed and a nut I 9 threading onto the screw and rotatably mounted in the lower portion of the casing 13 in which the nut is rotatably mounted and held against axial movement by bearings 20. The nut carries the planet gears 2| of the differential; the sun gear 22 01. which is driven through appropriate gearing 23 from the shaft of the rapid traverse motor N. The ring gear 24 is connected to the shaft 25 of the feed motor l5 by worm gearing 26 and 21 and speed change gearing 28 connecting two cross shafts 29 and 30. The ends of the latter terminate adjacent one side of the casing" so that they may be expos d by removal of a detachablecover 3|.

It will be observed that the nut [9 may be rotated by operation of either of the motors II and I5, and that it will be advanced along 'the screw in a direction and at a speed corresponding to that of the operating motor thereby causing corresponding motion of the tool head 'I as a unit. When the feed motor alone is operating,

the shaft 32 of the rapid traverse motor is held against rotation by a, spring applied friction brake 33 arranged to be released by a solenoid 34 which is energized whenever the rapid traverse motor is excited.

The speed change gearing 23 provides a means by which the rate of feed of the tool head may be varied for the performance of diii'erent metalremoving processes at optimum efliciency. For certain applications, this gearing may take the form of pick-off gears 35 (Fig. 2) removably attached to the outer ends of the shafts 29 and 30. Or, where a quicker change of the feed rate is desirable, a clutch-controlled speed change gearing may be employed. As shown in Fig. 9, such gearing may comprise a drive shaft 33 coupled to the shaft 29 within a housing 31 and having fast thereon gears 33 and 39 of different sizes which mesh with gears 43 and 4| loose on a shaft 42 coupled to the shaft 36. Splined on the latter is a toothed collar 43 adapted by actuation of a lever 44 to be shifted selectively into engagement with teeth on either of the gears 43 and 4| to establish high and low speed driving ratios respectively between the shafts 29 and 33. Through the medium of a suitable eccentric (not shown), the lever 44 may be swung from one of said positions to the other by means of a handle 45 disposed externally of the gear housing 31.

As will more fully appear later, thetoolscarried by the head I are mounted on spindles or shafts 46 (Fig. 3) projecting from a face plate 41 closing the forward end of the housing 43 of the tool unit II. The spindles 46 are journaled in the face plate with their axes located accurately according to the space of the holes to be formed.

\ To produce proper synchronism between the rotation of the tools and the axial feed thereof so as to enable tapping operations to be performed, the drive shafts 46 are driven from the feed motor I5. For this purpose, the motor shaft 25 is geared to a shaft 49 which extends through the forward end of the casing I3 intothe housing 43 where the shaft is connected by a selectively adjustable speed reducing mechanism 66 (Fig. 3) to a shaft 5| which, through appropriately designed gearing 62, drives the tool drive shafts at the proper relative speeds.

The speed reduction mechanism 66 comprises two gears 63 and 64 of different sizes coupled to a pinion on the end of the shaft 49 and meshing with gears 33 and 51 which are loose on the shaft 5| and arranged to be engaged selectively by an axially shiftable clutch collar 63 splined on the shaft. Through appropriate conpections (not shown) and a handle 69 (Fig. 1) disposed exteriorly of the housing 43, the collar may be shifted to establish selectively a high or low speed drive ratio for the tools.

It is contemplated that the mechanisms 23 and 63 will be so constructed that when the feed change mechanism 23 is set for its low driving ratio and the mechanism 53 is set for high speed, the proper tool drive and feed ratios for the drilling operation will be established. Similarly, the proper ratios for efficient tapping will be obtained when the mechanisms 23 and 63 are set for the high feed and the low tool drive ratios. In this way, the common drive mechanism may be conditioned for drilling or for tappi operations simply by adjustment of the levers 46 and 59 which, if desired, may be arranged for operation by a common actuating element.

Through the use of the single drive mechanism arranged for adjustment in the manner described to vary the rates of feed and tool drive, a-single control mechanism may be employed for governing the motors I4 and I5 to define automatically either a normal drilling cycle comprising rapid approach, feed and rapid return motions of the tool-head I or a tapping cycle comprising rapid approach, feed, reverse feed and rapid return motions.

In the form shown, the control mechanism comprises generally a series of switches 6|, 62, 63, and 64 governing the motor circuits and operated selectively by a series of relatively adjustable dogs 65', 65", and 65 spaced according to the lengths of the diiferentpaths of the cycles to be performed. Preferably the dogs operate to control the switches through the medium of a selector element 63 which is advanced unidirectionally with a step-by-step motion through a plurality of different positions in which the switches are conditioned for producing the different feed and rapid traverse motions.

Herein the dogs, which operate to determine the points in the movement of the tool head I at which different parts of a cycle are initiated and terminated, are carried by and spaced around a rotatable disk 69 positioned in the casing I3 so as to be exposed upon removal of a cover plate Ill. The dogs project parallel to the axis of the disk and are shaped to straddle a flange II to which they are adjustably clamped. The disk is detachably mounted on the end of a shaft I3 and is driven from the feed nut I9 through pairs of gears I4 and I5. v

Preferably, the selector element 33 which operates the switches to determine the character of .the different parts of each machine cycle is in the form of a cam shaft rotatably supported within the casing I3 and carrying a set of cams 3|, 32, 33* and 34! adapted to operate the switches 6|, 32, 63, and 64 to define a drilling cycle and a second set of cams 3|", 32 33 and 34 for defining a tapping cycle. In the present instance, the sets of cams are rendered operative selectively by shifting the cam shaft 63 axially in its bearings 36 so as to bring one or the other set of cams into operative association with pivoted follower arms 36 by which the switches are opened against the action of individual springs 31 which tend to maintain the switches closed. I

The cams and. followers are so constructed that in at least one-angular position, which is the normal starting position in the present instance, the cam shaft is free to move axially. To facilitate such movement, one end of the cam shaft isv coupled to a knob 33 journaled in an outwardly projecting flange 39 and operable from a point exteriorly of the casing I3. By retracting a set screw 93 (Fig. 8) to withdraw it from an annular locking groove 9I in the cam shaft, th latter may, by manipulation of the knob 33, be shifted axially to bring the other set of cams into operative association with the followers 36 and thereby condition the control mechanism for execution of a differentv end of the opening when the shaft is set for execution of a tapping cycle. These axial positions of the cam shaft may be indicated by suitable legends marked along the slot 99 on the outer surface of the flange 89.

A ratchet mechanism preferably of the mechanical type is employed for advancing the selector shaft 88 one step each time one of the dogs moves past a predetermined operating position. This mechanism includes a plunger 92 (Fig. 2) mounted for endwise reciprocation and carrying at one end a roller I99 in the path of the dogs and carrying a pawl 93 which operates on the teeth of an elongated ratchet wheel 94 I splined onto the inner end of the cam shaft 68.

1 by closure of the switch 94.

A second plunger 95 is urged into engagement with the ratchet wheel by a spring 99 so that after the pawl 93 has moved the ratchet wheel through a predetermined part of one step, the tapered end 91 of the plunger 95 will ride over center with respect to one of the ratchet teeth and act as a cam thereon to complete the step of movement with a snap action. The cams are shaped to operate their switches in this rapid portion of the cam shaft movements.

' As shown in the exemplarywiring diagram Fig. '7), the switches 6| and 62 operate through the medium of magnetic relay switches IM and I92 to control the feed motor I5. Energization of the coil I93 of the relay switch I9I closes switches which connect the power'leads I94, I95, and I99 to conductors I91, .98, and I99 in a manner such as to cause operation of the feed motor in a direction to move the tool head toward the work. Similarly, energization of the coil I II of the relay switch I92 connects the feed motor to the power leads in a manner such as to cause reverse rotation of the motor and retraction of the tool head away from the work. The switches 63 and 64 are arranged to connect the motor I I to the conductors I01 and I98 so that whenever the relay I9I is energized, closure of the switches 64 and 63 will cause the motor I3 to produce rapid approach and rapid return motions re spectively. When the relay I92 is energized, rapid return of the tool head will be produced Starting of each cycle and interruption of the motor operation at any point therein are controlled by normally open and normally closed switches I99 and H9 respectively.

With the levers 45 and 59 and. the cam shaft 68 set for the drilling cycle, the operation is as as follows, the switches being conditioned by their cams as shown in Fig. 10 and the follower roller I99 being in engagement with the dog 95 as indicated in Fig. 11. The cycle is started by closure of the start switch I99 which completes an energizing circuit for the relay coil I93 extending from the power conductor I95 through a conductor II2, the coil I93, a conductor II3, the switch I99, a conductor III, the then closed switch 62, a conductor II5, the then closed stop switch II9, a conductor III; to the power line I96. Closure of the relay switch I9I applies current to the feed motor I5, and since at this time the switches 64 are also closed, the motor I3 will also be started, rapid approach movement of the tool head being produced by the combined operation of the two motors.

Closure of a switch I" of the relay I9I establishes a locking circuit for the coil I93 including the stop switch II9.

In the first stepping movement of the cam shaft 68 during which the latter is advanced one eighth of a revolution and which occurs when the dog 95 actuates the plunger 92, a lobe on the cam 84 opens the switch 64 thereby interrupting the operation of the rapid traverse motor whereupon the feed motor continues to drive the tool and advance the same into the work at the proper speed for drilling. When the dog 65 becomes effective to advance the cam shaft in its second stepping movement, the follower controlling the switches 63 rides oil from a lobe on the cam 83 allowing these switches to close.

starting the rapid traverse motor. During the ensuing rapid return movement of the tool head,

the dog 95 causes a third or idle advance of the cam shaft 68 without changing the condition of the control switches so that the return of the head continues until the cam shaft is moved to its fourth position by the dog 95. In this advance, the follower of the cam 82 rides over a short lobe II8 to open the switch 62 momentarily thereby interrupting the locking circuit for the relay coil I93 so as to stop the feed and rapid traverse motor but leaving the switch 92 closed and thus conditioned for initiation of the next cycle. In the same advance of the cam the cam 84 allows the switches 94 to close.

. shaft, the cam 83 opens the switches 63 while For tapping operations, the levers 45 and 59 would be moved to their other positions and the knob 88 shifted to bring the cams 81 92 83 and 84 into operative association with the followers 85. To start the cycle, with the parts positioned as shown in Figs '1, 12 and 13, the switch I99 is closed momentarily causing the relay coil I93 to be energized and the feed and rapid traverse motors to be started in the manner above described. The cam shaft 68 remains stationary as the dog 65 moves away from the roller I99 and until the roller is engaged and the ratchet plunger is actuated by the dog 95". In the ensuing advance of the cam shaft, a lobe on the cam 84' opens the switches 64 whereupon the operation of the rapid traverse motor is interrupted, tapping of the holes occurring in the continued rotation of the taps and advance of the tool head produced in synchronism by the feed motor I5.

In the second step of movement of the cam shaft which is produced by engagement of the 'dog 85 with the roller I99, the follower 89 rides off from a lobe on the cam 8 I allowing the switch 6| to close and a lobe on the cam 82 opens the switch 62. The relay coil I93 is thus deenergized and the coil I I9 is energized thereby reversing the direction of rotation of thefeed motor I5 and the dog disk 69. The direction of rotation of the tool is thus reversed and the latter is withdrawn from the work at feed speed.

' When the dog 65 again engages the roller 96 and actuates the ratchet plunger to advance the cam shaft 98 in its third step, the follower for the cam 84 rides oif from a lobe on the latter allowing the switches 64 to close which again initiates the operation of the rapid traverse motor I4. But since the feed motor is now energized through the reverse relay switch I 92, the rapid traverse motor runs in the corresponding direction thereby producing rapid return of the tool head. The cycle is terminated automatically in the fourth movement of the cam shaft which is produced by the dog 65* and in which a lobe on the cam II opens the switch 6| to deenergize the relay coil I III, the switch 62 being allowed to close by the cam 62.

In addition to the manual setting of the cycle control mechanism and changing in the tool drive and feed ratios, conversion from a machine for efllciently drilling the holes I in the work piece 2 to one for emciently tapping these holes or vice versa involves a substitution of one set of tools for the other on the tool head I. To enable this to be accomplished quickly and conveniently in the machine shop, the invention contemplates rotatably mounting the tools of the two sets on carriers I2I and I22 (Figs. 1, 3 and 4) mountable interchangeably on the tool unit II for positioning the tools of each set in driving relation with respect to the respective drive spindles, thereby avoiding individual handling or adjustment of each tool in the conversion of the machine.

In the present instance, the carriers are in the form of plates which may, as shown in Fig. 3, be detachably and rigidly secured to the face plate 41 of the tool unit through the medium of a plurality of arms I23 rigid with the face plate and having threaded projections I24 at their ends onto which nuts I25 may be screwed to clamp the carrier rigidly to the arms. Holes I26 through which the projections I24 extend are of sufficient size to permit some degree of lateral shifting of the plate preparatory to clamping of the same to the arms I23 by tightening down the nuts I25.

The drills 5 are carried by individual spindles I26 projecting loosely through recesses I21 in the carrier plate with their axes located according to the spacing of the holes to be drilled. The spindles are held against axial movement relative to the plate by virtue of a shoulder I26 on one side of the plate and a snap ring I29 disposed between the other side of the plate and a shoulder I36. At their lower ends, the spindles are recessed to receive the threaded ends of chucks I3I in which the individual drills are secured.

Spindles I32 mounted in the tap carrier plate I22 are of the same construction as the spindles I26 with their lower ends recessed to receive the threaded shanks I33 of collets I34. The individual taps 6 are supported in the usual way in these collets for a limited degree of axial yielding movement to compensate for any slight inaccuracy in timing between the rotation and axial feed of the taps. Axial setting of each tap is effected by adjustment of a nut I35 threading onto the shank I33 which is held against rotation relative to the spindle by a key I36 and is supported by a set screw I 31 entering a tapered slot I38 in the shank.

It will be observed that the tools of each set are at all times supported .by their carriers in the same relation as the drive shafts 46 and may be brought into alinement with the latter simply by positioning the carrier. To avoid individual angular adjustment of the tools, provision is made for coupling of the drive shafts 46 to the spindles automatically as an incident to attachment of the carrier plate to the tool unit. This is accomplished by a quickly detachable coupling device having elements respectively mounted on the drive shaft and the corresponding spindle and adapted for positive interengagement in a predetermined angular relation of the drive sh'aft and the corresponding spindle. One of the elements is free to yield axially to permit of proper attachment of the carrier plate to the head even if the coacting coupling elements are not in exact mating relation and then come into mating engagement with the cooperating coupling element in the initial rotation of the drive shafts 46.

To form the coupling device, the upper reduced end I46 of each spindle I26 and I32 is received in the tubular lower end portion I of the drive shaft 46 and is formed with diametrically extending slot I42 which is adapted to receive the correspondingly shaped lower end portion of a coupling bar I43. The latter has arms I44 projecting through the slots I45 in the tubular portion I and is urged toward the spindle by a compression spring I46 opposite ends of which are seated in the bar I44 and the lower end of the drive shaft 46. It will be seen that if the bar I43 is not in alinement with the slot I45 when the carrier plate is attached to the tool unit, the bar will engage the end surface of the spindle shank MI and slide upwardly as shown in Fig. 6 against the action of the spring I46. Then, in the initial rotary motion of the drive shaft 46, the bar will turn with the shaft and be brought into mating relation with the slot whereupon the bar will be projected into the slot (Fig. 5). A positive driving connection between each tool spindle and its individual drive shaft 46 will thus be established automatically as an incident to the substitution of one set of tools for the other.

In the coupled relation, the shoulder I36 transmits the end thrust on the tools to the drive shaft 46 which herein is supported in anti-friction radial and thrust bearings formed by rollers I46 and balls I45 seated in a bushing I56 which projects through the face plate 41.. Pinions I5l by which the shafts 46 are driven from the gearing 52 are splined on the upper ends of the shafts.

Means is provided for facilitating location of the carrier plates on the tool unit II preparatory to final clamping of the plates in place. In the present embodiment, this means comprises dowel pins I52 rigid with cross bars I53 on the frame I54 of the work fixture and adapted to be received in holes I 55 when the carrier plate is placed on the fixture as shown in Fig. 4 with the thread projections I24 entering the proper holes in the plates.

Assuming that the taps 6 are to be substituted for the drills 5 mounted on the tool head as shown in Fig. 3, the procedure is as follows. After detachment and removal from the fixture of a plate I56 carrying the bushings I51 for guiding the drills 5, thetool head II is moved toward the fixture until the carrier plate I2I rests against the bars I53. Then the nuts I25 are removed, the plate I2I being supported by the dowel pins I22 and ledges I56 (Fig. 1) on the bars I53. Next the tool head is retracted, the carrier plate I2I removed and the tap plate I22 placed against the bars I53 as shown in Fig. 4 with the dowel pins I52 entering the holes I55. Then the tool head is advanced to enter the projections I24 through the holes I55 thereby locating the caps relative to the fixture. Complete entry of the spindle shanks I43 into the drive shafts 46 is permitted by yielding of those coupling ba s I43 which are not alined with the slots I42. Finally, the nuts I25 are tightened onto the projections I 24 to clamp the piate I22 in proper position on the tool head. In the first tapping operation, the couplings between the drive shafts and spindles will be completed as above described.

Removal of the tap carrier and substitution of the drill curier I2I therefor is effected In a and I22 will be attached permanently to the machine and arranged to be swung or shifted into and out of operative position.

We claim as our invention:

1. A multiple spindle machine tool head for facilitating "quick interchange of tools thereon comprising, incombination, a gear housing having a wall with laterally spaced spindle openings therein, a series of spindles rotatably supported by .said housing to turn about axes extending through said openings and having ends accessible from the exterior ot-said housing, power driven means within said housing for driving said spindles,'a carrier structurally separate from said housing, a. plurality of tool-carrying spindle extensions supported by said carrier with their axes spaced for simultaneous alinement with the axes ranged tov interengage in at least one angular relation of the spindle and extension and provide a positive driving connection therebetween when said carrier is moved to a predetermined position opposite said wall with said extensions alined with the respective spindles, one of said elements being mounted to yield and permit full movement of the carrier to saidposition with the mating 1 elements of certain of said pairs disposed out of said anguler relation whereby to permit of ready separation of said carrier with said extensions thereon from said housing and the substitution of another carrier with similarly spaced tools of different characten' 2. A multiple spindle machine tool head for facilitating quick interchange of tools thereon comprising, in combination, a gear housing having awall with laterally spaced spindle openings therein, a series of spindles rotatably supported by said housing to turn about axes extending through said openings and having ends accessible from the exterior of said housing, power driven means within said housing for driving said spindles, a plurality of spindle extensions each carrying a tool on one end, the other end extensions and the accessible end of one of said spindles being constructed to interfit throughout a substantial distance in telescoping relation and co acting independently of said carrier to effect accurate lateral location of the tools on said extensions, and coacting coupling elements on each spindle and the extension thereof interchangeable in positive driving relation, and a single structurally separate carrier rotatably supporting said extensions with their axes in the same spaced parallel relation as said spindles whereby to permit the spindle extensions to be handled as a unit when detached from said spindles and to be maintained in positions for simultaneous coupling with the respective spindles in the movement of the carrier toward said wall.

ALEXANDER. OBERHOFFKEN. EARL M. BOWEN. 

